PlzNavigate: Add first version of NavigationURLLoader.

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index b4548badd1cc14dc6af7557853f3fbf6cae4fcdb..453151fb143dbcfe090e3f62b7c8533e06df74cc 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -54,6 +54,7 @@ class ShareableFileReference;
 }
 
 namespace content {
+class NavigationURLLoaderCore;
 class ResourceContext;
 class ResourceDispatcherHostDelegate;
 class ResourceMessageDelegate;
@@ -256,21 +257,14 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // elsewhere.
   void FinishedWithResourcesForRequest(const net::URLRequest* request_);
 
-  // PlzNavigate
-  // Called by NavigationRequest to start a navigation request in the node
-  // identified by |frame_node_id|.
-  void StartNavigationRequest(const CommonNavigationParams& common_params,
+  // PlzNavigate: Begins a request for NavigationURLLoader. |loader| is the
+  // loader to attach to the leaf resource handler.
+  void BeginNavigationRequest(ResourceContext* resource_context,
+                              int64 frame_tree_node_id,
+                              const CommonNavigationParams& common_params,
                               const NavigationRequestInfo& info,
                               scoped_refptr<ResourceRequestBody> request_body,
-                              int64 navigation_request_id,
-                              int64 frame_node_id);
-
-  // PlzNavigate
-  // Called by NavigationRequest to cancel a navigation request with the
-  // provided |navigation_request_id| in the node identified by
-  // |frame_node_id|.
-  void CancelNavigationRequest(int64 navigation_request_id,
-                               int64 frame_node_id);
+                              NavigationURLLoaderCore* loader);
 
  private:
   friend class ResourceDispatcherHostTest;